Hello Devesh Saini,

                     Yes, with 89.4 percentile in JEE Mains, you have some chances to get a seat in Amrita University. Although, it hugely depends on the scores of other students applying for the same and the stream of your choice. Since Amrita University takes admission through AEEE also, only 30% of the seats will be alloted on the basis of JEE Mains percentile. So, a percentile of around 95 will be required to get a seat in Amrita University. 

For further details, visit the following website:

https://www.amrita.edu/sites/default/files/information-handbook-btech-admissions-2019.pdf

Hope it helps!